Holden's hunting hat
Holden's hat was used to portray his longing to be different. The way J.D Salinger confirms this is the way Holden always puts the hat on in a goofy fashion and Holden doesn't care what others think. The color red possibly caught Holden's attention because of coincidentally being the color of his younger brother Allie's hair. Allie passed away a while back and Holden misses his company and the hat probably reminds him of Allie. Holden loves his hunting hat and treasures wearing it throughout the story.

The Museum
In The Catcher in the Rye, Holden talks about his trip to the Museum of Natural History and also visits it himself. In the book, Holden explains how symbolic the figures in the museum are. The figures never change throughout the years and years that they have been displayed, while everyone and everything around them is constantly changing. They are symbolic because Holden wishes to be where he never has to change and where innocence is the dominant trait. It troubles him because he himself is changing, while the figures he saw years ago are the same years later. Holden's wish is to live in the museum with the unchanging figures so he does not have to be in a world of constant change.

The Carousel
The carousel in the end of the book is the symbol for Holden's final realization that he can not protect his little sister Phoebe forever. He sees her trying to reach for the golden ring as the carousel goes round and around. She may fall and get hurt, but that is a mistake that she will learn from in order to grow up. Holden realizes that life experiences are important and change is inevitable throughout life. He concludes that his dream of a never changing world and becoming a "catcher in the rye" is childish and pointless because experiencing mistakes, conflicts, and change in life are all crucial to growing up.